The present invention relates to a backrest height adjusting assembly and, more particularly, to a height adjusting assembly for adjusting a height of a backrest while providing an excellent and reliable positioning effect.
A type of chair includes a backrest at a rear side of a seat to permit a user to lie his or her back against the backrest. The backrest is fixed to the seat or a chassis plate disposed on the bottom side of the seat. The backrest has a contour corresponding to the curvature of the back of the human body to provide improved lying comfort. However, the contour of the backrest cannot suit different users having different heights, failing to provide reliable lying comfort and failing to provide wide applications.
To solve the above drawbacks, a type of chair includes a backrest having a tube at a lower end thereof. A post is disposed on top of a chassis plate of the seat. The tube is coupled with the post, and a knob transversely extending through the tube is tightened to fix the height of the backrest relative to the seat. When height adjustment of the backrest is desired, the knob is released, the backrest is moved to a desired height, and the knob is re-tightened. The whole adjusting procedure is troublesome. Furthermore, the backrest could loosen and move downward if the knob is not tightened, failing to provide a reliable adjusting effect.